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I am seeing a negative peak in my reversed phase chromatogram. I am using a UV detector. What is causing this?

GENERAL TROUBLESHOOTING

HPLC UHPLC REVERSED PHASE

Last Updated: 5/4/2014

Any difference in the mobile phase and sample will cause a “peak”; i.e. regardless any change in mobile phase composition will cause a response. So, if the absorbance of a solute is less than that of mobile phase, this can cause a negative peak. As such, this method may require a mobile phase with a lower UV absorbance.